Here's what Mager had to say about the value proposition for businesses:

Businesses that are adjacent to BART stations also benefit from a Foursquare partnership: people add tips about places nearby when they checkin to the station, and other users benefit. Advertisers win in this situation too.

It's not just for local mom-and-pop joints, either: imagine gaining insight into the habits of customers who check-in to a certain airport gate, or gaining more knowledge about the habits of customers who travel through certain areas of the city.

Some examples: a financial district; a garment district; a hip neighborhood; a stroller-strewn 'nabe.

What do you think: the next step in smarter transportation? Or simply better, more targeted mobile advertising?